Extent of Lymphadenectomy and Outcome for Patients With Stage I Nonsmall Cell Lung Cancer

BACKGROUND: It is uncertain whether lymphadenectomy (LA) affects overall survival (OS) or disease-free survival (DFS) rates for patients with stage I nonsmall cell lung cancer (NSCLC), as is the optimal number of lymph nodes that should be recovered. METHODS: There were 24,273 patients with stage I NSCLC diagnosed from 1992 to 2002 who were included in the Surveillance, Epidemiology, and End Results database and who underwent a definitive surgical procedure. Median follow-up was 35 months. RESULTS: For the entire population, having LA was associated with an increase in the 5-year OS rate from 41.6% to 58.4% (P<.0001) and in DFS from 58.0% to 73.09%, compared with not having LA. Outcome improved with increasing number of recovered lymph nodes, with a plateau at 11 or more lymph nodes. For patients diagnosed from 1998 to 2002 undergoing only N1 or only N2 dissections, LA was also associated with statistically significant improvements in OS in both groups and a significant difference and trend for improved DFS in the 2 groups, respectively. The maximum differences in both OS and DFS between those with no LA and those with LA occurred when 11 to 16 lymph nodes were removed for the former group or 7 to 10 lymph nodes for the latter group, respectively. CONCLUSIONS: LA was associated with increased rates of OS and DFS, compared with no LA. Our results also suggest the minimum number of recovered lymph nodes needed to see the maximum staging accuracy conferred by LA. Cancer 2009;115:851-8. (C) 2009 American Cancer Society.